Error in get_monitors() for SAMSUNG monitor

[nowdob]

• Monitor manufacturer and model number: SAMSUNG and LED Monitor (S24F354FH)
• Input source (HDMI, VGA, display port, ect.): HDMI
• Output device (video card, discrete graphics, ect.): discrete graphics
• Operating system: window 10
• Python version: 3.9.0
• monitorcontrol version (monitorcontrol --version): 2.5.1

Steps to Reproduce

I wrote some test code as below. It works well for LG monitor.
However when I tried it with samsung monitor, I got error of InputSourceValueError(255).
I think it fails to get monitor information after software power off for samsung monitor.

I'd like to control monitor power for energy saving.
It would be great if you check it

---

for monitor in get_monitors():
    with monitor:
        monitorSrc = monitor.get_input_source()  
        if monitorSrc.value != 0:
            monitor.set_power_mode("off_soft")    # succeed to turn off the monitor

time.sleep(5.0)

for monitor in get_monitors():   
    with monitor:
        monitorSrc = monitor.get_input_source()    # raise InputSourceValueError: 255 is not a valid Input Source
        if monitorSrc.value != 0:
            monitor.set_power_mode("on")        

[newAM]

Some monitors will cease to respond to DDC-CI commands when in standby or power off, they do it as a power saving feature. Check if your monitor has any power settings in the on-screen menu that could change the behavior.

[nowdob]

Thanks for your reply. I'll check related option. In this regard, I have one more question.
If I get return value of inputSource.OFF in get_input_source() function for some monitor. Could I think that the monitor doesn't support DDC-CI commands?

FYI, I experienced that if it got inputSource.OFF return value, I failed turn on or off the monitor during test.

[newAM]

There is no good way to determine if a monitor supports DDC-CI or not. Somtimes it is supported but disabled in the on screen display. What the monitor returns when it is off or isn't supported is vendor specific.